Analysis of electric signal generated from CFRP for sensing function of smart civil engineering structures

Fiber-reinforced plastic (FRP) is a material used to reinforce civil engineering structures. Carbon-fiber-reinforced plastic (CFRP) is composed of conductive reinforcing filler and dielectric matrix. By utilizing the internal structure of CFRP and the difference in electrical conductivity of the components, carbon fiber (CF) and resin matrix can serve as a structural electrode and a frictional material, respectively. Electrostatic charge is generated by friction between resin covering CF and external materials. It induces an alternating current through CF according to the distance change between charged layers. Then, CFRP can be applied as a structural sensor using the triboelectric effect. In this research, we identified the triboelectric effect occurring on the surface of the composite and the electrostatic induction phenomenon occurring inside the composite. In addition, the voltage signal changes according to the movement of external materials. By identifying the effects that occur in composite materials, we have confirmed the possibility of realizing a smart civil engineering structure that can detect touch by itself.